Based on the characteristics of high power diesel engines’ thermal balance analysis, a diesel engines’ thermal balance test and analysis system is developed through dealing a large number of test data. This system can real time monitor the temperature, pressure and flow rate of the components in cooling circuit, fuel circuit and gas circuit, can continuously record and store the state parameters, can realize theory computation, statistical analysis, query, and print data report. Also the system can realize remote operation. This system has already been operated in several enterprises. Results show that the system can estimate diesel engines’ thermal balance effectively. According to the analysis results, diesel engines’ designers can estimate the components that bearing excessively high thermal load and can solve the thermal balance problem of high power engines.